1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * Definitions for the UDP module. 8 * 9 * Version: @(#)udp.h 1.0.2 05/07/93 10 * 11 * Authors: Ross Biro 12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 13 * 14 * Fixes: 15 * Alan Cox : Turned on udp checksums. I don't want to 16 * chase 'memory corruption' bugs that aren't! 17 */ 18 #ifndef _UDP_H 19 #define _UDP_H 20 21 #include <linux/list.h> 22 #include <linux/bug.h> 23 #include <net/inet_sock.h> 24 #include <net/sock.h> 25 #include <net/snmp.h> 26 #include <net/ip.h> 27 #include <linux/ipv6.h> 28 #include <linux/seq_file.h> 29 #include <linux/poll.h> 30 #include <linux/indirect_call_wrapper.h> 31 32 /** 33 * struct udp_skb_cb - UDP(-Lite) private variables 34 * 35 * @header: private variables used by IPv4/IPv6 36 * @cscov: checksum coverage length (UDP-Lite only) 37 * @partial_cov: if set indicates partial csum coverage 38 */ 39 struct udp_skb_cb { 40 union { 41 struct inet_skb_parm h4; 42 #if IS_ENABLED(CONFIG_IPV6) 43 struct inet6_skb_parm h6; 44 #endif 45 } header; 46 __u16 cscov; 47 __u8 partial_cov; 48 }; 49 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb)) 50 51 /** 52 * struct udp_hslot - UDP hash slot 53 * 54 * @head: head of list of sockets 55 * @count: number of sockets in 'head' list 56 * @lock: spinlock protecting changes to head/count 57 */ 58 struct udp_hslot { 59 struct hlist_head head; 60 int count; 61 spinlock_t lock; 62 } __attribute__((aligned(2 * sizeof(long)))); 63 64 /** 65 * struct udp_table - UDP table 66 * 67 * @hash: hash table, sockets are hashed on (local port) 68 * @hash2: hash table, sockets are hashed on (local port, local address) 69 * @mask: number of slots in hash tables, minus 1 70 * @log: log2(number of slots in hash table) 71 */ 72 struct udp_table { 73 struct udp_hslot *hash; 74 struct udp_hslot *hash2; 75 unsigned int mask; 76 unsigned int log; 77 }; 78 extern struct udp_table udp_table; 79 void udp_table_init(struct udp_table *, const char *); 80 static inline struct udp_hslot *udp_hashslot(struct udp_table *table, 81 struct net *net, unsigned int num) 82 { 83 return &table->hash[udp_hashfn(net, num, table->mask)]; 84 } 85 /* 86 * For secondary hash, net_hash_mix() is performed before calling 87 * udp_hashslot2(), this explains difference with udp_hashslot() 88 */ 89 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table, 90 unsigned int hash) 91 { 92 return &table->hash2[hash & table->mask]; 93 } 94 95 extern struct proto udp_prot; 96 97 extern atomic_long_t udp_memory_allocated; 98 99 /* sysctl variables for udp */ 100 extern long sysctl_udp_mem[3]; 101 extern int sysctl_udp_rmem_min; 102 extern int sysctl_udp_wmem_min; 103 104 struct sk_buff; 105 106 /* 107 * Generic checksumming routines for UDP(-Lite) v4 and v6 108 */ 109 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb) 110 { 111 return (UDP_SKB_CB(skb)->cscov == skb->len ? 112 __skb_checksum_complete(skb) : 113 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov)); 114 } 115 116 static inline int udp_lib_checksum_complete(struct sk_buff *skb) 117 { 118 return !skb_csum_unnecessary(skb) && 119 __udp_lib_checksum_complete(skb); 120 } 121 122 /** 123 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments 124 * @sk: socket we are writing to 125 * @skb: sk_buff containing the filled-in UDP header 126 * (checksum field must be zeroed out) 127 */ 128 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb) 129 { 130 __wsum csum = csum_partial(skb_transport_header(skb), 131 sizeof(struct udphdr), 0); 132 skb_queue_walk(&sk->sk_write_queue, skb) { 133 csum = csum_add(csum, skb->csum); 134 } 135 return csum; 136 } 137 138 static inline __wsum udp_csum(struct sk_buff *skb) 139 { 140 __wsum csum = csum_partial(skb_transport_header(skb), 141 sizeof(struct udphdr), skb->csum); 142 143 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) { 144 csum = csum_add(csum, skb->csum); 145 } 146 return csum; 147 } 148 149 static inline __sum16 udp_v4_check(int len, __be32 saddr, 150 __be32 daddr, __wsum base) 151 { 152 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base); 153 } 154 155 void udp_set_csum(bool nocheck, struct sk_buff *skb, 156 __be32 saddr, __be32 daddr, int len); 157 158 static inline void udp_csum_pull_header(struct sk_buff *skb) 159 { 160 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE) 161 skb->csum = csum_partial(skb->data, sizeof(struct udphdr), 162 skb->csum); 163 skb_pull_rcsum(skb, sizeof(struct udphdr)); 164 UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr); 165 } 166 167 typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport, 168 __be16 dport); 169 170 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_head *, 171 struct sk_buff *)); 172 INDIRECT_CALLABLE_DECLARE(int udp4_gro_complete(struct sk_buff *, int)); 173 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *, 174 struct sk_buff *)); 175 INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int)); 176 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb, 177 struct udphdr *uh, struct sock *sk); 178 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup); 179 180 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, 181 netdev_features_t features); 182 183 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb) 184 { 185 struct udphdr *uh; 186 unsigned int hlen, off; 187 188 off = skb_gro_offset(skb); 189 hlen = off + sizeof(*uh); 190 uh = skb_gro_header_fast(skb, off); 191 if (skb_gro_header_hard(skb, hlen)) 192 uh = skb_gro_header_slow(skb, hlen, off); 193 194 return uh; 195 } 196 197 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */ 198 static inline int udp_lib_hash(struct sock *sk) 199 { 200 BUG(); 201 return 0; 202 } 203 204 void udp_lib_unhash(struct sock *sk); 205 void udp_lib_rehash(struct sock *sk, u16 new_hash); 206 207 static inline void udp_lib_close(struct sock *sk, long timeout) 208 { 209 sk_common_release(sk); 210 } 211 212 int udp_lib_get_port(struct sock *sk, unsigned short snum, 213 unsigned int hash2_nulladdr); 214 215 u32 udp_flow_hashrnd(void); 216 217 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb, 218 int min, int max, bool use_eth) 219 { 220 u32 hash; 221 222 if (min >= max) { 223 /* Use default range */ 224 inet_get_local_port_range(net, &min, &max); 225 } 226 227 hash = skb_get_hash(skb); 228 if (unlikely(!hash)) { 229 if (use_eth) { 230 /* Can't find a normal hash, caller has indicated an 231 * Ethernet packet so use that to compute a hash. 232 */ 233 hash = jhash(skb->data, 2 * ETH_ALEN, 234 (__force u32) skb->protocol); 235 } else { 236 /* Can't derive any sort of hash for the packet, set 237 * to some consistent random value. 238 */ 239 hash = udp_flow_hashrnd(); 240 } 241 } 242 243 /* Since this is being sent on the wire obfuscate hash a bit 244 * to minimize possbility that any useful information to an 245 * attacker is leaked. Only upper 16 bits are relevant in the 246 * computation for 16 bit port value. 247 */ 248 hash ^= hash << 16; 249 250 return htons((((u64) hash * (max - min)) >> 32) + min); 251 } 252 253 static inline int udp_rqueue_get(struct sock *sk) 254 { 255 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit); 256 } 257 258 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if, 259 int dif, int sdif) 260 { 261 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 262 return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept, 263 bound_dev_if, dif, sdif); 264 #else 265 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); 266 #endif 267 } 268 269 /* net/ipv4/udp.c */ 270 void udp_destruct_sock(struct sock *sk); 271 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); 272 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb); 273 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb); 274 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 275 int noblock, int *off, int *err); 276 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, 277 int noblock, int *err) 278 { 279 int off = 0; 280 281 return __skb_recv_udp(sk, flags, noblock, &off, err); 282 } 283 284 int udp_v4_early_demux(struct sk_buff *skb); 285 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); 286 int udp_get_port(struct sock *sk, unsigned short snum, 287 int (*saddr_cmp)(const struct sock *, 288 const struct sock *)); 289 int udp_err(struct sk_buff *, u32); 290 int udp_abort(struct sock *sk, int err); 291 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 292 int udp_push_pending_frames(struct sock *sk); 293 void udp_flush_pending_frames(struct sock *sk); 294 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size); 295 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 296 int udp_rcv(struct sk_buff *skb); 297 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); 298 int udp_init_sock(struct sock *sk); 299 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 300 int __udp_disconnect(struct sock *sk, int flags); 301 int udp_disconnect(struct sock *sk, int flags); 302 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait); 303 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 304 netdev_features_t features, 305 bool is_ipv6); 306 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 307 char __user *optval, int __user *optlen); 308 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 309 sockptr_t optval, unsigned int optlen, 310 int (*push_pending_frames)(struct sock *)); 311 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 312 __be32 daddr, __be16 dport, int dif); 313 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 314 __be32 daddr, __be16 dport, int dif, int sdif, 315 struct udp_table *tbl, struct sk_buff *skb); 316 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, 317 __be16 sport, __be16 dport); 318 struct sock *udp6_lib_lookup(struct net *net, 319 const struct in6_addr *saddr, __be16 sport, 320 const struct in6_addr *daddr, __be16 dport, 321 int dif); 322 struct sock *__udp6_lib_lookup(struct net *net, 323 const struct in6_addr *saddr, __be16 sport, 324 const struct in6_addr *daddr, __be16 dport, 325 int dif, int sdif, struct udp_table *tbl, 326 struct sk_buff *skb); 327 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, 328 __be16 sport, __be16 dport); 329 330 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid 331 * possibly multiple cache miss on dequeue() 332 */ 333 struct udp_dev_scratch { 334 /* skb->truesize and the stateless bit are embedded in a single field; 335 * do not use a bitfield since the compiler emits better/smaller code 336 * this way 337 */ 338 u32 _tsize_state; 339 340 #if BITS_PER_LONG == 64 341 /* len and the bit needed to compute skb_csum_unnecessary 342 * will be on cold cache lines at recvmsg time. 343 * skb->len can be stored on 16 bits since the udp header has been 344 * already validated and pulled. 345 */ 346 u16 len; 347 bool is_linear; 348 bool csum_unnecessary; 349 #endif 350 }; 351 352 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb) 353 { 354 return (struct udp_dev_scratch *)&skb->dev_scratch; 355 } 356 357 #if BITS_PER_LONG == 64 358 static inline unsigned int udp_skb_len(struct sk_buff *skb) 359 { 360 return udp_skb_scratch(skb)->len; 361 } 362 363 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 364 { 365 return udp_skb_scratch(skb)->csum_unnecessary; 366 } 367 368 static inline bool udp_skb_is_linear(struct sk_buff *skb) 369 { 370 return udp_skb_scratch(skb)->is_linear; 371 } 372 373 #else 374 static inline unsigned int udp_skb_len(struct sk_buff *skb) 375 { 376 return skb->len; 377 } 378 379 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 380 { 381 return skb_csum_unnecessary(skb); 382 } 383 384 static inline bool udp_skb_is_linear(struct sk_buff *skb) 385 { 386 return !skb_is_nonlinear(skb); 387 } 388 #endif 389 390 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, 391 struct iov_iter *to) 392 { 393 int n; 394 395 n = copy_to_iter(skb->data + off, len, to); 396 if (n == len) 397 return 0; 398 399 iov_iter_revert(to, n); 400 return -EFAULT; 401 } 402 403 /* 404 * SNMP statistics for UDP and UDP-Lite 405 */ 406 #define UDP_INC_STATS(net, field, is_udplite) do { \ 407 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 408 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 409 #define __UDP_INC_STATS(net, field, is_udplite) do { \ 410 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 411 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 412 413 #define __UDP6_INC_STATS(net, field, is_udplite) do { \ 414 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\ 415 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 416 } while(0) 417 #define UDP6_INC_STATS(net, field, __lite) do { \ 418 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \ 419 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 420 } while(0) 421 422 #if IS_ENABLED(CONFIG_IPV6) 423 #define __UDPX_MIB(sk, ipv4) \ 424 ({ \ 425 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 426 sock_net(sk)->mib.udp_statistics) : \ 427 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \ 428 sock_net(sk)->mib.udp_stats_in6); \ 429 }) 430 #else 431 #define __UDPX_MIB(sk, ipv4) \ 432 ({ \ 433 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 434 sock_net(sk)->mib.udp_statistics; \ 435 }) 436 #endif 437 438 #define __UDPX_INC_STATS(sk, field) \ 439 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field) 440 441 #ifdef CONFIG_PROC_FS 442 struct udp_seq_afinfo { 443 sa_family_t family; 444 struct udp_table *udp_table; 445 }; 446 447 struct udp_iter_state { 448 struct seq_net_private p; 449 int bucket; 450 struct udp_seq_afinfo *bpf_seq_afinfo; 451 }; 452 453 void *udp_seq_start(struct seq_file *seq, loff_t *pos); 454 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 455 void udp_seq_stop(struct seq_file *seq, void *v); 456 457 extern const struct seq_operations udp_seq_ops; 458 extern const struct seq_operations udp6_seq_ops; 459 460 int udp4_proc_init(void); 461 void udp4_proc_exit(void); 462 #endif /* CONFIG_PROC_FS */ 463 464 int udpv4_offload_init(void); 465 466 void udp_init(void); 467 468 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key); 469 void udp_encap_enable(void); 470 #if IS_ENABLED(CONFIG_IPV6) 471 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key); 472 void udpv6_encap_enable(void); 473 #endif 474 475 static inline struct sk_buff *udp_rcv_segment(struct sock *sk, 476 struct sk_buff *skb, bool ipv4) 477 { 478 netdev_features_t features = NETIF_F_SG; 479 struct sk_buff *segs; 480 481 /* Avoid csum recalculation by skb_segment unless userspace explicitly 482 * asks for the final checksum values 483 */ 484 if (!inet_get_convert_csum(sk)) 485 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM; 486 487 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or 488 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial 489 * packets in udp_gro_complete_segment. As does UDP GSO, verified by 490 * udp_send_skb. But when those packets are looped in dev_loopback_xmit 491 * their ip_summed is set to CHECKSUM_UNNECESSARY. Reset in this 492 * specific case, where PARTIAL is both correct and required. 493 */ 494 if (skb->pkt_type == PACKET_LOOPBACK) 495 skb->ip_summed = CHECKSUM_PARTIAL; 496 497 /* the GSO CB lays after the UDP one, no need to save and restore any 498 * CB fragment 499 */ 500 segs = __skb_gso_segment(skb, features, false); 501 if (IS_ERR_OR_NULL(segs)) { 502 int segs_nr = skb_shinfo(skb)->gso_segs; 503 504 atomic_add(segs_nr, &sk->sk_drops); 505 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr); 506 kfree_skb(skb); 507 return NULL; 508 } 509 510 consume_skb(skb); 511 return segs; 512 } 513 514 #ifdef CONFIG_BPF_STREAM_PARSER 515 struct sk_psock; 516 struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 517 #endif /* BPF_STREAM_PARSER */ 518 519 #endif /* _UDP_H */ 520